What about a bit of ethidium bromide, then irradiate with a hand-held uv
light? (assuming that your DNA is ds). Never tried this, but it might work.
Jacob
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
Dallos Laboratory
F. Searle 1-240
2240 Campus Drive
Evanston IL 60208
lab: 847.491.2438
cel: 773.608.9185
email: j-kell...@northwestern.edu
*******************************************
----- Original Message -----
From: "Nick Quade" <nick.qu...@helmholtz-hzi.de>
To: <CCP4BB@JISCMAIL.AC.UK>
Sent: Tuesday, June 23, 2009 8:06 AM
Subject: [ccp4bb] Detection of DNA in protein complex crystals
Dear all,
I am trying to solve the structure of a transcription factor in complex
with its DNA. I got crystals of the complex under different conditions
than the protein alone and they also look different. Unfortunately, they
only diffract to 6Å so far. Before I continue to optimize the crystals I
would like to confirm that the crystals really contain the bound DNA.
Thus I tried to crystallize the protein alone under the same conditions
as the complex which did not give crystals. I also tried to stain the
crystals with methylene blue, but that did not work (but staining with
IZIT did not work either). Additionally I dissolved a crystal and
measured the absorption. The ratio between A260 and A280 was 1.3. So
there seems to be DNA, but less than there should be.
Does any of you know a good way to quickly but reliably confirm the
presence of DNA in my crystals?
Thanks a lot in advance.
Nick
